a light microscope, visible light is passed through a specimen and then through

glass lenses. The lenses refract the light is such a way that the image of the

specimen is magnified as it is projected into the eye, onto photographic film

or digital sensor, ot onto a video screen.

how does an electron microscope work?

1) In

an electron microscope it focuses a beam of electrons through the specimen or

onto its surface.

describe the structer of membranes

made up of phospholipid bilayer and proteins

proteins components

organic

compounds made of amino acids

-

Glycoprotein components and function

contain

glycan covalently attatched to polypeptide side chains.

- They allow certain types of cell-to-cell communication, help coordinate

complicated cellular responses to stimuli, and activate the action of other

types of cells.

what is a glycoglipid composed of and its function

glipids

with carbohydrate attatched

-are carbohydrate attached lipids. Their role is to provide energy and also

serve as markers for cellular recognition.

cholesterol

waxes,

steroid, metabolite. Found in cell membrane

whats the difference between a transmembrane and peripheral proteins

1) Transmembrane are embeded into the membrane and peripheral are loosely attatched to the outside.

transport protein-

hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane

enzymatic protein

a protein built into the membrane may be an enzyme with its ative site exposed to substances in the adjacent solution.

signal transduction psirotein

A membrane protein (receptor)may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. the external messenger may cause a shape change in the protein that relays the message to the inside of the cell

intercellular joining protein

membrane bound proteins of adjacent cells may hook together in various kinds of junctions such as gap junctions or tight junctions